圆的扇形面积演示 by Linda Fahlberg-Stojanovska

GeoGebra 命令及参数

1. Polygon((0, 0), (base, 0), (base, r), (0, r)) → poly1, a, b, c, d
2. Circle(A, r) → e
3. Point(e) → B
4. Rotate(B, 360 * ° / n, A) → B'
5. Segment(B, B') → dx
6. Midpoint(dx) → C
7. Segment(A, C) → dy
8. Sequence(Rotate[B, j * 360 * ° / n, A], j, 0, n) → list1
9. Sequence(CircleSector[A, Element[list1, j], Element[list1, j + 1]], j, 1, n, 2) → list2
10. Sequence(CircleSector[A, Element[list1, j], Element[list1, j + 1]], j, 2, n, 2) → list3
11. Sequence(CircleSector[(j * dx + dx / 2, dy), (j * dx + 0, 0), (j * dx + dx, 0)], j, 0, n / 2 - 1) → list5
12. Sequence(CircleSector[(j * dx, 0), (j * dx + dx / 2, dy), (j * dx + (-dx) / 2, dy)], j, 1, n / 2 - 1) → list4
13. CircleSector((0, 0), (dx / 2, dy), (0, dy)) → wedgeS
14. CircleSector((n / 2 * dx + 0, 0), (n / 2 * dx, r), (n / 2 * dx - dx / 2, dy)) → wedgeE
15. Segment(D, D') → f
16. Midpoint(f) → E
17. Segment(A', E) → g